The man who helped bring the Smurfs to America was busted yesterday for allegedly trying to shake down his son-in-law – a deep-pocketed executive at a top private equity firm – for $11 million, authorities said.

Stuart Ross, 71, of Aventura, Fla., was charged with unleashing a campaign of harassment against his son-in-law David Blitzer, a senior managing director at the Blackstone Group, the Manhattan District Attorney’s Office announced.

Ross’s 79-year-old New York attorney, Stuart Jackson, was also charged with attempted grand larceny for his role in the scheme. Both face up to seven years in prison.

Ross was traveling in Belgium in 1976 when he discovered the popular French-language European cartoon known as “Les Schtroumpfs” and decided it could become big in America.

He bought North American rights to the tiny characters with blue skin and white caps, who live in mushrooms and battle the evil wizard Gargamel. Renamed Smurfs for a US audience, they became hugely popular as dolls and an animated early ’80s Hanna-Barbera TV show.

Ross was also producer of a 1983 movie, “The Smurfs and the Magic Flute.” But over the years, Ross lost his cartoon fortune.

Ross – whose daughter Allison is Blitzer’s wife – had long been estranged from the family after telling her he wished her unborn child would die and that obscenities should be carved on her gravestone, according to a civil lawsuit Blitzer filed separately.

Ross had also walked off with $195,000 Blitzer gave him to start an Internet business, the suit said. Ross then disappeared from the couple’s lives for many years.

In December 2007, Ross called Blitzer and got the son-in-law to give him $65,000 for seed money to start a business venture.

Then in June, Ross allegedly began bombarding Blitzer with nonstop phone calls and e-mails demanding more cash and threatening to damage his reputation and ruin his career. He also started calling Blitzer’s bosses at Blackstone in a bid to discredit him.

“David, this is your worst nightmare,” he said in one call, according to the civil suit. “I’m going to continue to harass you. I am going to call you every day – four or five times a day – I am going to keep calling.”

On Thursday, Blitzer met with Jackson and Ross and agreed to give them $400,000. The two men were arrested yesterday.